Recent regulations have lowered the acceptable total arsenic level in drinking water to 10 Au/L.
The arsenic levels in the two groundwater wells operated by the Walker River Paiute Tribe have
been measured to range between 70 and 110 Au/L. A treatment technology is needed that can
consistently reduce these levels to below regulatory limits. In addition to arsenic, significant
levels of silica (54 mg/L) and an "elevated" pH (8.6) are present that must be addressed when
selecting the appropriate treatment technology.
The raw water quality can influence the effectiveness of the treatment options evaluated. The
range of selected raw water quality parameters encountered during the study are presented in the paper.
The ranges experienced were not considered unusual, as the Tribe generally draws
alternately from two well sources for varying times. The arsenic was speciated on-site and
subsequently determined to be all in the As<sup>+5</sup> state.
Seven technologies were evaluated through either bench- or pilot-scale testing for their ability to
consistently remove arsenic. The technologies included coagulation/microfiltration (C/MF),
coagulation with conventional direct filtration, coagulation with high-rate direct filtration,
granular ferric hydroxide (GFH), iron doped activated alumina (AA FS-50), iron doped natural
zeolite (Z-33), and ion exchange. The results of the study indicated that each technology was
capable of removing arsenic from the Tribe's water. However, not every technology could
consistently remove arsenic below the MCL or run for acceptable operation times.
Includes tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 260 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 5 |
| Published : | 11/02/2003 |
